Plate Tectonics Review Vocab

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the process by which sediment settles out of the water or wind carrying it.

erosion

the destructive process in which water or wind loosens and carries away fragments of rock; moving or transporting materials.

weathering

breaking down of the Earth's surface - chemical and physical process.

glacier

a large mass of moving ice and snow over land.

sea-floor spreading

the process by which molten material adds new oceanic crust to the ocean floor.

volcano

a weak spot in the Earth's crust where magma has come to the surface; divergent boundaries: small, low volcanic mountains; less violent eruptions.convergent boundaries: violent eruptions.hot spots: line of volcanoes that form in the middle of plates as they move.

hot spot

a volcano forms above a hot spot when magma erupts through the crust and reaches the surface.

Hawaiian Islands

a chain of island volcanoes formed by a hot spot.

asthenosphere

the soft layer of the mantle on which the lithosphere floats.

lithosphere

a rigid layer made up of the upper most part of the mantle and the crust.

trench (deep ocean)

deep under water canyon formed where subduction occurs; the deepest part of the ocean floor.

mountains

when a continental plate is involved at a convergent boundary - mountains are formed on the edge of the continental plate; both folded and volcanic.

mid-ocean ridge

an undersea mountain chain where new ocean floor is produced; a divergent plate boundary.

rifting

the tension force of the plates pulling apart has caused huge cracks (faults) where large chunks of the Earth's crust sink and force up magma causing volcanoes.

convection currents in the asthenosphere

the movement of a fluid, caused by differences in temperature, that transfers heat from one part if the fluid to another; the magma in the mantle heats up when it is close to the core, which makes it less dense. This causes it to rise towards the crust. When it gets close to the crust, it cools down which mkase it more dense and it sinks.